is going. If it is leaking out in 4 minutes you should see it on the floor. I have rented the radiator pressure testers from the local auto parts house to help find the smaller leaks. You could also check your oil and see if it is a "milky" white/brown combination that would indicate a defective head gasket or cracked head(worse case). A bad turbo seal will generally smoke at idle and during deceleration. At this point I would definitely start off locating the coolant leak and then go from there with the general maintenance items referenced above. Good luck and keep us posted